In the related art, a film-forming process for forming a film on a substrate accommodated in a process chamber is described as one of the manufacturing processes of a semiconductor device.
In the film-forming process, a precursor gas and a reaction gas are supplied to a process chamber accommodating substrates stacked in the vertical direction, thereby forming a film on each of the stacked substrates. When forming the film on each of the substrates stacked in a vertical direction as described above, the film thickness sometimes varies depending on the positions at which the substrates are disposed.